Henry Morris, who died Saturday at 87, was perhaps the most influential creationist of the 20th century, an author of myriad books and tracts and founder of an institute dedicated to scientifically proving that the earth was created in six days, just a few thousand years ago.

A hydraulic engineer by training, Morris was especially drawn to the story of Noah’s flood. He called his theory “Biblical Catastrophism,” and contended that a correct interpretation of scripture could account for everything from the Grand Canyon to complicated mineral stratigraphy that orthodox science holds can only be accounted for by the passage of billions of years.

For Morris, the scientific consensus that the earth was billions of years old was proof that evolution was no more scientific than religion, because, he contended, scientists were unwilling to question orthodox views. They ignored the earth’s allegedly decaying magnetic field, refused to consider the role of rapid erosion in creating landforms, or the possibility that God had placed fossils underground for mankind’s edification. Paleontologists had never produced a fossilized “transitional form” of the sort evolution required. Man was not a monkey. Dinosaurs, Morris mused, might have been passengers aboard Noah’s Ark, and become extinct later.

The alternative to biblical literalism, Morris suggested, was godless materialism, the survival of the fittest, and the perfidious theory of evolution which led, he darkly warned, to everything from communism to “animalistic amoralism.”

Morris began a career in Christian apologetics while in graduate school for engineering, at the University of Minnesota, producing pamphlets and books. In 1951, a year after he received his doctorate, he published “The Bible and Modern Science.” He simultaneously produced books on engineering with titles like “Hydraulics of Flow in Culverts” (1948) and “Applied Hydraulics in Engineering” (1963), a widely used textbook. By 1957, when he became a professor of engineering at Virginia Tech, he was already working on “The Genesis Flood.”

According to the paleontologist Stephen Jay Gould, “The Genesis Flood” (1961) is “the founding document of the creationist movement.” At well over 500 pages, the book treated in seemingly comprehensive detail questions of the depth of the flood, the size of the Ark, the destruction of humanity, geology, hydrology, and even the problem of carbon-14 dating. The earth, Morris concluded, was between 6,000 and 10,000 years old. His position became the founding document of what is known as “young earth creationism,” still the most popular form of creationism in America, the executive director of the National Association for Science Education and a prolific anti-creationist writer, Eugenie Scott, said. The book is still in print 45 years later, and it has sold well over 150,000 copies, its publisher, Presbyterian and Reformed Publishing, reports.

Despite his growing fame in Christian creationist circles, Morris stayed at Virginia Tech, keeping his position as head of the civil engineering department and his career as an anti-evolutionary writer largely separate. “I just didn’t do leisure sports during my downtime like golf and fish,” Morris told the Roanoke Times last December. “I spent my time writing.” He helped found a church, but by 1970 was feeling increasingly alienated from colleagues, some of whom considered him a crank.

In 1970, he decamped for San Diego, where he teamed with the flamboyant clergyman Tim LaHaye to found Christian Heritage College. LaHaye is more famous today as author of the megaselling “Swept Away” series of Christian apocalypse books.

Morris served initially as academic dean of Christian Heritage, and also as director of the college’s Institute for Creation Research. In 1980, the institute became an independent institution, and today is accredited to teach graduate-level classes in biology and geology. It is generally seen as the most influential institution of faith-oriented science, with more than a dozen faculty members with doctorates in science. Among its ongoing research projects have been several expeditions sent to eastern Turkey to search for the remains on Noah’s Ark on the slopes of Mount Ararat. No luck so far.

Morris continued writing for a growing audience, books with titles like “The Remarkable Birth of Planet Earth,” “The Revelation Record,” and “Their Words May be Used Against Them,” a collection of quotes from evolutionary scientists to be deployed in debates. He wrote at least 60 books in all.

Despite the confrontational tone of many of the books (e.g. “The Long War Against God”), Morris was in person a friendly man, described as tolerant and even encouraging of dissent and free inquiry. He opposed the mandatory teaching of creation science in the classroom. “Anytime you tell a teacher that he has to teach something, he’s probably not going to do it very well,” Morris told the Chicago Tribune in 1976.

“I don’t think anybody on our side of the issue believed that Henry was anything other than sincere,” Ms. Scott said. “The evidence to prove creationism was just around the corner.”

In 1996, Morris turned the reins of the ICR over to his son, John Morris, a young-earth geologist. He still wrote prolifically, but began taking up more conventionally religious themes as he confronted old age, and contemplated the Psalms, Jonah, and Job.

Henry Madison Morris

Born October 6, 1918, in Dallas; died February 25 at a hospice in Santee, Calif., after a series of strokes; survived by his wife of 66 years, Mary Louise Morris, five children, 17 grandchildren, and nine great-grandchildren.